Communication systems in which information processing apparatuses, such as computers, are connected to each other with wireless communication means, such as a WLAN (wireless local area network) or Bluetooth®, to transmit and receive information including files and data and to share the information are generally built along with advancement of information technology.
In recent years, long-range-communication-function mounted apparatuses, in which communication devices capable of long range communication using Bluetooth or the like are mounted on mobile phones or personal computers, are used to transmit and receive large volume data including moving picture data and music data (for example, refer to Japanese Unexamined Patent Application Publication No. 2003-324446).
In order to reduce the risk in security in the long-range data communication, introduction of data encryption processes becomes common even in the long range communication. The risk in security includes sniffing of data by third parties with long-range-communication-function mounted apparatuses and alternation of data.
It is necessary to identify communication partners in order to perform the encryption process in the long range communication adopting Bluetooth or the like. However, unexpected long-range-communication-function mounted apparatuses are possibly identified as the communication partners because of the wide communication area of the long range communication.
Even if the communication partners are identified, it is necessary to share a session key used for starting more secure communication between the communication partners. However, there is a possibility that the session key is sniffed and decrypted by the third parties with the long-range-communication-function mounted apparatuses when the session key is transmitted to the communication partner, because of the wide communication area of the long range communication. Accordingly, it is necessary to increase the strength of the session key, for example, by lengthening the keys and, therefore, to provide a higher processing power to the long-range-communication-function mounted apparatuses.
Accordingly, it is an object of the present invention to provide new and improved communication system and communication apparatus, which are capable of easily identifying a communication partner and securely sharing a session key between the communication apparatus the communication partner even if the communication apparatus has a processing power that is not so high.